The present invention relates to ballistic ceramic armor. More specifically, the present invention pertains to ballistic ceramic armor made from an alpha-beta SiAlON ceramic material that exhibits excellent ballistic performance results, as well as provides other advantages over earlier ceramic armor materials. An alpha-beta SiAlON ceramic material is a ceramic that contains an alpha SiAlON phase (which can also be referred to as an alpha-prime SiAlON phase or an α-SiAlON phase or an α′—SiAlON phase) and a beta SiAlON phase (which can also be referred to as an beta-prime SiAlON phase or an β-SiAlON phase or an β-SiAlON phase), as well as optional intergranular phases such as a glassy phase (which is typically amorphous) and/or a crystalline phase.
Ballistic ceramic armor is intended to be worn by a user for protection, as well as for use in protecting light mobile equipment and vehicles, against high-speed firearm projectiles (e.g., bullets) and fragments (e.g., shrapnel). There are three main considerations concerning protective ballistic armor materials.
The first consideration for protective ballistic armor is the weight of the armor. Protective armor for heavy, but mobile, military equipment (e.g., tanks and large ships), is known. Such armor usually comprises a thick layer of alloy steel, which is intended to provide protection against heavy and explosive projectiles. Because of the large size of this equipment, the greater weight of the alloy steel kinds of armor is not a significant consideration for equipment such as tanks and ships. However, due to its greater weight, such armor is quite unsuitable for light vehicles such as automobiles, jeeps, light boats, or aircraft, whose performance is compromised by armor that is of a greater weight. The same is true for body armor designed to be worn by a user in that heavy body armor is undesirable and impractical.
While specifications for body armor and armor for light vehicles may vary upon the specific application, armor suitable for these kinds of applications must prevent penetration of bullets of any weight at high speeds (e.g., speeds in the range of 700 to 3000 meters per second). Further, armor suitable for these kinds of applications must satisfy certain weight limitations (e.g., an armor weight which is acceptable for use on light vehicles varies with the type of vehicle, but generally falls in the range of 40 to 70 kg/m2).
It can thus be appreciated that it would highly desirable to provide a ballistic armor, and especially a ballistic ceramic armor, that is able to satisfactorily prevent penetration of projectiles even when traveling at high speeds. It can also be appreciated that it would be highly desirable to provide such a ballistic ceramic armor that is sufficiently lightweight so as to not impede the performance of light vehicles or individuals in the case of ballistic ceramic body armor.
The cost of the material is a second consideration concerning protective ballistic armor materials. In the case of overly complex armor arrangements, particularly those arrangements depending entirely on synthetic fibers, it has been found that the armor arrangement comprises a notable proportion of the total vehicle cost. In such a situation, the result can be that manufacture of the vehicle is not profitable due to the cost of the ballistic armor component. It can therefore also be appreciated that it would be highly desirable to provide a ballistic armor, and especially a ballistic ceramic armor, that is affordable to make wherein the affordability of the armor results from one or both of the cost of materials and the cost of manufacture of the ballistic ceramic armor.
A third consideration in armor design is compactness of the ballistic armor bodies or components. A thick armor panel, including air spaces between its various layers, increases the target profile of the vehicle, as well as increases the wind resistance of the vehicle. As can be appreciated, each one of these results is undesirable in that it makes the vehicle more susceptible to compromise to attack by an enemy. In the case of vehicles retrofitted with internal ballistic armor (e.g., civilian automobiles or even military vehicles needing more armor protection), there oftentimes is a lack of apace to affix a thick panel to those areas that require protection. It can thus be appreciated that it would be highly desirable to provide a ballistic armor, and especially a ballistic ceramic armor, that presents a compact design so as to take up less space than heretofore thicker armor panels, and thus, be suitable to retrofit existing vehicles.
Heretofore, ceramic materials have been considered as potential candidates for use as ballistic armor. Silicon carbide and boron carbide are two especially suitable ceramic material candidates for ballistic ceramic armor. Exemplary patent documents that describe these kinds of ballistic ceramic armor materials, as well as other kinds of ceramic armor materials, include the following: U.S. Pat. No. 6,805,034 B1 to McCormick et al. for Silicon Carbide Armor Bodies, and Methods for Making Same, U.S. Pat. No. 7,104,177 B1 to Ahajanian et al. for Ceramic-Rich Composite Armor, and Methods for Making Same, and U.S. Pat. No. 7,117,780 to Cohen for a Composite Armor Plate.
Although current ballistic ceramic armor materials may provide satisfactory performance results, there remains a need to provide an improved ballistic ceramic armor whereby such armor addresses the above-mentioned design considerations for ballistic armor. In this regard, the improved ballistic ceramic would be able to satisfactorily prevent penetration of projectiles even when traveling at high speeds, as well as be sufficiently lightweight so as to not impede the performance of light vehicles or individuals in the case of ballistic ceramic body armor.
Further, such improved ballistic ceramic armor would be affordable to make wherein the affordability of the armor results from one or both of the cost of materials and the cost of manufacture of the ballistic ceramic armor. In reference to the method of manufacturing, such improved ballistic ceramic armor would provide the capability to be made into more complex shapes or geometries than heretofore available. This would be due to the ability to make the ceramic by methods (e.g., sinter-HIP techniques) that allow for more flexibility than earlier methods (e.g., hot pressing techniques).
In addition, such improved ballistic ceramic armor would present a compact design so as to take up less space than heretofore thicker armor panels, and thus, be suitable to retrofit existing vehicles. The capability to make ballistic ceramic armor of more complex shapes facilitates activities like the retrofitting of existing vehicles.